[MB968]

Having played a bit with wild cams, I can attest to the lowered vacuum that can result. So, timing of the cam does seem like a valid candidate.



So, this is a clarification question. I know our engine if an interference engine, but is it possible to mark the current location of the cam and then make small adjustments one way or the other to see if it will make any difference in the vacuum. I don't think there is more than a few degrees "slop" in the key/keyway joint, so you can't go too far. But, can anyone confirm that you can move the timing within the manufactured play in the key/keyway without having a potential issue with the interference. I can't imagine a designer putting in enough play to allow a problem, but?? Anyone have any actual experience with this on our engine?

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

[quote name='tamathumper' timestamp='1374015930' post='145715']

I've spoken to both the local dealer and the only trustworthy shop in the area, neither of which wants to tackle timing my car, so it may not be too far off topic after all...

[/quote]

Fair enough. Looking forward to a description from KRAG50 as to how he managed to pressurize his variocam with oil.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

vliegwielolaf1234 did exactly that in a recent post (and a follow-up IM or two), but hopefully he'll elaborate more here.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Yes, I have heard of people who have done it, so I'd like to hear what type of rig they connected their variocam to to pressurize it with oil. Also, my understanding was that timing the cams with oil pressurization is the most accurate way to do it with the engine in the car, yet KRAG50 seemed to express some doubt (if I'm reading his post right) as to the accuracy of his final timing, so I'd like to hear him elaborate on that.

Partial Post: Please Login or Register to read the full post.

[flash]

it's really little more than an oiler with pressure behind it. you can use an air compressor to pump an oil head into the valve. all you need to do is get oil in there so it holds position properly. it's very much like an automatic transmission valve.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

OK, thanks. Chances are there's a youtube video on something like this.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Looks like a constant flow of air/oil is required, at 3 bar. I wonder how much pressure those 12V oil change pumps put out - they are designed to run a hose down the fill tube and suck oil out of the sump, and pump it into a container, but maybe one could be rigged to feed it into the VarioCam...

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

[quote name='tamathumper' timestamp='1374057561' post='145749']

Looks like a constant flow of air/oil is required, at 3 bar. I wonder how much pressure those 12V oil change pumps put out - they are designed to run a hose down the fill tube and suck oil out of the sump, and pump it into a container, but maybe one could be rigged to feed it into the VarioCam...

[/quote]

Sounds like a potential project in the making. By the way, you cigar-based smoke test rig worked perfectly on my daughter's E46 - it pinpointed the source of the leak.

Partial Post: Please Login or Register to read the full post.

[vliegwielolaf1234]

First , there is no danger that the pistons hit the valve when adjusting the cam's full aft or forward , that is with the belt installed correct and on the timing marks .



Then the air at 3 bar works , but and to my opinion timing it with a oil fed hose is a bit over the top if you ask me , the air wil work just fine if you use the 3bar pressure .

If you do want to go with oil i think you do not need a lot of pressure , a little flow would allready do the trick since the oil does not compress and leak out like air like flash allready mentioned .



The change in vacuum is also there with the standard cams and it could be part of your hesitation issue .

I my case after the <acronym title='mass air flow'>MAF</acronym> failure i think that part was the main problem , but i changed to many thing to be 100% on that being the only problem .



I also noticed that advancing the cam's wil make the engine responde a lot more aggresive , as long as you don't open it all the way then it kind off just keeps on hanging for a while , retarding the cam's feels a little more soft but it wil go beter on full throttle .

Partial Post: Please Login or Register to read the full post.

[flash]

using air only works on a wet valve. that is what the procedure was written for. if you are rebuilding your engine, and are not installing a new valve, it might NOT work properly. air passes right by the valve and your timing can be off as much as 13 degrees. that is EXACTLY how i found this out. you have to degree in the cams to know for sure though, and that is very difficult with the engine in the car. that is why they wrote the procedure the way they did. it's just about the only way the porsche dealerships could do it without them having to get another tool just for this job. it was all about cost. we got screwed again.



just to be clear, and i won't get into which is advanced and which is retarded, as those often get confused, and what some people think is advanced is really retarded (i smell a politically incorrect joke there) but increasing the overlap on a supercharged engine is a bad idea. boost goes where it does not want to, as does exhaust. at lower rpms you'll gain some snap, but once things get flowing it gets dangerous. intake temps soar and you can easily detonate.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

flash, did you mean to say "If you are rebuilding your engine, and ARE installing a new valve..."?

Partial Post: Please Login or Register to read the full post.

[flash]

no - a new valve just might seal up enough, but a cleaned out old one probably won't. that's what happened to me. it's really no different than rebuilding an engine, but re-using the rings and expecting it to seal up.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

A bit of exchange with KRAG50 helped me understand the air/oil separator - both where the heck it is, and how to spray enough schmoo on it to see if it's leaking. It is. And just for the record, it takes a lot of schmoo. Just before reaching 5 psi, I hear a "pop" somewhere, so there's definitely a seal flapping in and out of *something*. Rubber and plastic get old. Now to figure out how to get at that @#$! thing - it's buried under the intake manifold, so that is definitely coming off. There may just be a trip to the shop in the future - I just don't have any time with everything else that's going on.

Partial Post: Please Login or Register to read the full post.

[flash]

yup - no way to get at it without removing the manifold.



there is no flapper or anything inside it. i've cut one open to see. not sure what the "pop" is, but it isn't there.



as for leaking, i would definitely nail down exactly where it is leaking before diving in. when i did mine, i had to get the new one from germany. the o-rings were no big deal though.



you could put a check valve on that, which could solve a problem in one direction

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Well, it's leaking for sure, so it has to be fixed, but I hear you about finding out what else might be leaking before getting started. Whether or not it's *the* leak will have to be up to the shop - they probably have a better smoke machine with more PSI and it's not leaking at 1 or 2 psi, it waits until it gets to 3 then it starts hissing, and conversely it falls from 5 to 3 psi quickly, then slows considerably.



It's a pretty general sound, no way to pin it down, but from where it *sounds* like it's coming, the "pop" might be the O-rings, there are a couple nipples into the crankcase area, or it might be one of the oil seals for the spark plug holes, under the valve cover, there's a little oil in the second hole back. Time to pull the cover and replace everything in there, too, and inspect the Variocam pads and verify the timing at the same time.

Partial Post: Please Login or Register to read the full post.

[flash]

use a hose to your ear with everything under pressure and poke around see if you can nail down exactly where the leak is. the time lag on getting a new AOS is a killer. plus, it isn't inexpensive

Partial Post: Please Login or Register to read the full post.

[tamathumper]

I've been poking around with a hose in my ear for quite a while, and I can convince myself there is a faint hiss around the AOS (and there are certainly some bubbles forming when I spray a lot of Ajax on it), but I'll be damned if there are any other spots that seem to be hissing. Like I said, it's time for the shop to worry about it. I'm not concerned about the cost of the parts. My time is very scarce now and I've missed a month of driving due to travel and other projects (house water and ant damage). !@#$!

Partial Post: Please Login or Register to read the full post.

[flash]

well, as the device is designed to allow "breathing" between the crankcase and the intake, it will ALWAYS have a faint hiss of sorts.



the way to track this down is to disconnect every vacuum device, cap off all ports, and then add them back one at a time, until you find the one that is leaking.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Spent 250 dollars yesterday for the dealer to not find the leak at the air oil separator and to point out a tiny leak around the adjustment bolt of the adjustable fuel pressure regulator. TINY TINY. So I tested a lot this morning and found they may have overpressurized, as I now have leaks around the center two spark plugs at the cover, so the cam cover came off this morning and all the seals and gaskets are on order. I also hear a hiss somewhere around the blowoff valve but could not locate it with spray bubbles so I tightened all clamps to no avail. I also realized there is a hole in the bottom of the cam housing where the oil pipe comes in for the VarioCam, and that would be a perfect candidate for both the mystery hiss and the mystery oil drop that causes a little wisp of smoke and oil smell sometimes when warming up. Others have complained of a leak at this location. There is no o-ring, just a gasket. Oh, and there is still a small leak at the air oil separator... :/

Partial Post: Please Login or Register to read the full post.

[flash]

i too am concerned that you over-pressurized things. much more than 5lbs and you could easily blow things.



i have a call in about your AFPR leak

Partial Post: Please Login or Register to read the full post.